Partial dynamical symmetry versus quasi dynamical symmetry examination within a quantum chaos analyses of spectral data for even–even nuclei

Journal Article · 11 August 2021 · Scientific Reports

DOI: https://doi.org/10.1038/s41598-021-95847-1 · OSTI ID:1816662

Sabri, H. ^[1]; Mobarakeh, S. K. Mousavi ^[2]; Majarshin, A. J. ^[3]; Luo, Yan-An ^[4]; Pan, Feng ^[5]

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1. Univ. of Tabriz (Iran). Dept. of Physics; OSTI
2. Univ. of Tabriz (Iran). Dept. of Physics
3. Nankai Univ., Tianjin (China). School of Physics; Liaoning Normal Univ., Dalian (China). Dept. of Physics
4. Nankai Univ., Tianjin (China). School of Physics
5. Liaoning Normal Univ., Dalian (China). Dept. of Physics; Louisiana State Univ., Baton Rouge, LA (United States). Dept. of Physics and Astronomy

Statistical analyses of the spectral distributions of rotational bands in 51 deformed prolate even–even nuclei in the 152 ≤ A ≤ 250 mass region $$R_{{4_{1}^{ + } /2_{1}^{ + } }} \ge 3.00$$ are examined in terms of nearest neighbor spacing distributions. Specifically, the focus is on data for 0⁺, 2⁺, and 4⁺energy levels of the ground, gamma, and beta bands. The chaotic behavior of the gamma band, especially the position of the $$2_{\gamma }^{ + }$$ band-head compared to other levels and bands, is clear. The levels are analyzed within the framework of two models, namely, a SU(3)-partial dynamical symmetry Hamiltonian and a SU(3) two-coupled quasi-dynamical symmetry Hamiltonian, with results that are further analyzed using random matrix theory. The partial and quasi dynamics both yield outcomes that are in reasonable agreement with the known experimental results. However, due to the degeneracy of the beta and gamma bands within the simplest SU(3) picture, the theory cannot be used to describe the fluctuation properties of excited bands. By changing relative weights of the different terms in the partial and quasi dynamical Hamiltonians, results are obtained that show more GOE-like statistics in the partial dynamical formalism as the strength of the pairing term is increased. Also, in the quasi-dynamical symmetry limit, more correlations are found because of the stronger couplings.

• Research Organization: Louisiana State Univ., Baton Rouge, LA (United States); Texas A & M Univ., Commerce, TX (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• Grant/Contract Number: SC0005248; SC0009971
• OSTI ID: 1816662
• Journal Information: Scientific Reports, Journal Name: Scientific Reports Journal Issue: 1 Vol. 11; ISSN 2045-2322
• Publisher: Nature Publishing GroupCopyright Statement
• Country of Publication: United States
• Language: English